So I got this Audiosource S3D60 soundbar as a B stock manufacturer refurb for under $40 an Amazon...total score...I'm pretty happy considering I have been listening to TV speakers for the past year!!

I have my sub connected to one channel of the pre-out. When I change the volume from the soundbar remote there is no change to the subwoofer volume. So when I turn it down all the way I hear rumbles from the sub and when I crank it up the sub isn't loud enough! WTF over?!

I've always used receivers with SUB OUT options so is this a case of the soundbar just not adjusting the gain on the line level outputs? Or is it something where I need to use the line out in stereo? I'm like

I have both optical audio and analog stereo audio for the input...you can switch between inputs so I tried both. Same result. And I'm taking one channel (1 red or 1 white) out to the sub. No the sub isn't part of the system.

On page two under Line Output it says: "This output can be connected to an external subwoofer using standard RCA cables to add even more bass output to your listening experience. The output of this jack will track the volume of your source."